The present invention relates to a discharging container having a filter and adapted for use as an aseptic eyedropper, and also to a stopper for closing the container. Particularly, the invention relates to a discharging container comprising a stopper and a laminated bottle including a delaminatable inner layer such that a liquid medicine stored therein can flow out without allowing any amount of ambient air to flow into the bottle.
Collyria are solutions or liquid suspensions of ophthalmologic medicines, that may alternativey be dissolved or suspended in time of use. Such collyria are kept sterilized for application to conjunctival sac, and the term xe2x80x9ccollyriaxe2x80x9d used herein includes eyewashes.
Collyria are dozes to eyes that are one of the most delicate organs in ever human body, and inflamed eyes are most sensitive to foreign matters. Therefore, preparation of collyria has to be done very carefully in order to keep an aseptic condition such that not only any pathogenic bacteria are alive but also any harmless bacteria are shut out completely. Even such an aseptic condition is not satisfactory, but collyria must be prepared milch more carefully lest they should be contaminated with any pyrogens and/or any amount of insoluble foreign matters.
Generally, eyedropping squeeze-bottles (viz., eyedropping containers) contain therein collyria to be distributed to users for use as eyedroppers The bodies of such eyedropping bottles are usually formed of plastics, and proper examples thereof are polyethylenes, polypropylenes, polycarbonates, polyarylates and polyethylene terephthalates. In case of such collyrium-containers, it is very important requirements that they be transparent to such a degree as enabling visual check of foreign matters from outside, and has a low permeability for vapor so as to avoid concentration of collyria due to vaporization loss of water in the container. In addition, many proposals were made to improve the prior art eyedropping containers so as to surely prevent bacteria or the like foreign matters from entering the containers and thereby rendering them non-sterilized in usage as well as in distribution. Further, those prior proposals were designed to disinfect any bacteria accidentally present in the collyria being dropped into eyes.
For the purpose of sterilizing containers once unsealed, certain reserving agents may be added to collyria (viz., contents of the containers). Examples employable as such reserving agents are polymixin sulfates, quarternary ammonium compounds, chlorobutanols, organic mercury compounds, esters of p-hydroxybenzoic acid and alcoholic derivatives thereof. These reseving agents will, despite their excellent effect of killing microbe and bacteria, possibly cause various ophthalmogical inflammation or other serious damages after repeated use. Allergic reaction may be caused to some contact lens wearers even by reserving agents contained in low concentration.
Certain filters have been proposed to selectively remove such medically ineffective additives. These filters will remove said ineffective additives from the liquid medicine (viz., a collyrium) flowing through a dispensing passage in a bottle before discharged in a dropping manner. Japanese Patent Laying-Open Gazettes No. 4-297264 and No. 6-14972 describe such a filter that is disposed in the dispensing passage formed through each eyedropper. These prior art eyedroppers will however fail to diminish the concentration of the reserving agents sufficiently if they are contained rich enough to ensure a satisfactory sterilization effect. Since those prior art eyedroppers are of such a structure that bacteria are not shut out but carried by ambient air into the collyria, concentration of the reserving agents cannot be made low but has to be high enough to disinfect such a contaminated collyria. As a result, a noticeable amount of the reserving agents will unavoidably remain in the collyria having passed the filter before dropped.
On the other hand, Japanese Utility Model Gazette No. 63-184037 discloses a certain hydrophilic permeable membrane that is disposed in a discharging aperture through which eye drops filled in a container body arc exuded. This membrane allows the eye drops to pass through it, but stops bacteria and air not to flow into the container body. The container body in this utility model may be a tube having a depressed end, or be shaped foldable into a depressed configuration so that inner volume of said body gradually decreases as its content is consumed. In this type of prior art eyedropper, flow of ambient air into the container is prevented perfectly, protecting the liquid medicine from contamination with bacteria, thus realizing a lowest possible concentration of reserving agents to be added to said medicine. Since the container body of a monolayer structure has to deform itself plastically, it will be difficult to mold it using any plastics. Thus, aluminium tubes or the like must be used to manufacture such container bodies, thereby rendering them untransparent against the general rules prescribed for eyedroppers in the Japanese Pharmacopoeia. In addition, such container bodies that will become depressed more and more along the course of usage are difficult to stand upright during storage and less convenient to use.
An object of the present invention made in view of these drawbacks is therefor to provide a discharging container comprising a squeeze-bottle adapted for use as eyedroppers and capable of satisfying the transparency requirement. This discharging container must be improved to perfectly shut off ambient air and bacteria not to flowing into a liquid content retained in the container. This means that such container has to be kept sterilized even after unsealed for use. Another object of the invention is to provide a stopper designed to be used in such a discharging container.
A discharging container with a filter provided herein comprises a laminated bottle and a stopper attached to a finish of the laminated bottle, wherein the bottle is composed of an outer layer and an inner layer delaminatable therefrom. A vent hole is formed in the outer layer so as to introduce ambient air in between the outer and inner layers. A discharging passage is formed in the stopper to exude therethrough a liquid content retained inside the inner layer, with the filter being disposed together with a check valve in the discharging passage.
In use, the check valve will inhibit ambient air from entering the space defined by and in the inner layer. Consequently, the inner layer will deflate as the liquid content is consumed, with the liquid content being protected from contamination with bacteria which would otherwise be carried by ambient air into that space. Ambient air is however allowed to flow inwards in between the outer and inner layers through the vent hole, so that the outer layer once pressed with fingers or the like to exude the liquid content will restore its normal shape due to elastic recovery, until the container becomes empty. The container of the invention maintains its outer configuration unchanged from the beginning to end of usage, thereby enabling it to stand upright during storage and rendering it more convenient to use. Since the inner layer deflates and ambient air is prevented from flowing into the inner layer as mentioned above, despite gradual consumption of the liquid content, any reserving agents need not be added for the purpose of durable sterilization. Further, any resin materials may be employed to manufacture the inner and outer layers, if they are transparent to the required degree and do function as a good gas barrier and a good water vapor barrier. Thanks to these features, the container will show excellent performances as an eyedropper.
Preferably, a further check valve may be disposed in the vent hole so as to permit ambient air to flow in a space defined by and between the inner and outer layers and to prevent the ambient air having entered this space from flowing out through the outer layer. If such a further check valve is incorporated, then the squeezing of the outer layer will compress the air held in that space to raise its pressure, which in turn will depress the inner layer to exude the liquid content through the discharging passage. If contrarily no such check valve is employed, then users of this container will need to close the vent hole with their fingers or the like when they squeeze the outer layer of container.
The container of the invention has in its discharging passage the filter as discussed above, so that the bacteria floating within ambient air are stopped not to enter the bottle through said passage. Thanks to this feature, the interior of this bottle once opened will be kept sterilized even in a case wherein a very slight or no amount at all of reserving agent is added to the content. In another case wherein significant quantities of reserving agents are used to be present in the liquid content, the filter may preferably be designed such that bacteria are inhibited from passing through it and reserving agents are selectively removed from it.
The filter may be located downstreamly of the check valve first mentioned above. The liquid content portion stagnant around the check valve, particularly in the downstream side thereof, is also protected by the filter so as not to contact the ambient air. Bacteria will thus be inhibited to propagate in the stagnant portion of liquid content, thereby making it possible to secure a sufficient space between the check valve and the filter wide enough to allow the check valve to be smoothly opened and closed, with the space being protected from the breeding or propagation of bacteria.
The stopper which the present invention provides from another aspect is one to be attached to a finish of the bottle and does comprise a discharging passage for dispensing a liquid content held in the bottle, a check valve disposed in the discharging passage, and a filter also incorporated therein and located downstreamly of check valve.
The check valve may have a valve hole constituting a part of the discharging passage and a valve body for closing the valve hole from its downstream side, wherein the valve body closing the valve hole can be displaced downstreamly to open it. A free space is defined between the valve hole and the filter so as to permit displacement of the valve body.
The valve body may be formed integral with a cylindrical member, disposed between the valve hole and the filter so that this member holds the filter in place in the passage.
A deformable thin piece or pieces may connect the cylindrical member to the valve body continuing therefrom.
The filter may be formed such that bacteria are inhibited from passing from the downstream side to the upstream side of the filter.
The discharging passage may have, downstreamly of the filter, a region whose volume is not larger than one drop of the liquid content being exuded dropwise out of said passage.
The bottle may comprise a cap attachable to the bottle""s finish, with a projection protruding from the cap so as to fit in and engage with the discharging passage region located downstreamly of the filter. The stopper according to the invention in this case may have, as the passage region located at downstream side of the filter, a cavity that will be fully occupied by the projection.
The check valve may be designed such that inward flow of the ambient air into the bottle is prevented but the liquid content of the bottle can flow out of the bottle.